Alignment for equations

Question

Due to a physical disability using pen and paper for maths problems is not an option for me. So I am using Latex to work on maths problems, typically algebra at the moment. To be clear I'm using Latex not to print or share documents with other people but as a means of working on the algebra. [Note: I am a Linux user and have been unable to find a decent dedicated equation/formula editor that is suitable for my needs.]

The various equation commands that I've tried, IEEEeqnarray, eqnarray, align, all center the equations in the middle of the page. I can align the equations left, but that just means the beginning of each equation line is aligned on the left but the equations are still in the middle of the page. I would like the whole block aligned left on the left of the page.

I've used \usepackage[margin=2cm]{geometry} to set the page margins how I want them, and plain text appears where I want it, but the equations all end up in the middle of the page.

The image below shows what I mean and the red line shows where I would like the equations to actually begin. How do I achieve this please?

Here's the current Latex.

\documentclass[12pt,a4paper]{article}

\usepackage[margin=2cm]{geometry}
\usepackage{amsmath, amssymb, IEEEtrantools}

\begin{document}

This is some text to show the top left margin.

\begin{IEEEeqnarray*}{l}
x^4 - 13x^2 + 36 = 0 \\
\\
u = x^2 \\
u^2 - 13u + 36 = 0 \\
(u-9)(u-4) = 0 \\
u = 4, u = 9 \\
\\
x^2 = 4 \\
x = \pm \sqrt{4} \\
x = \pm 2 \\
\\
x^2 = 9 \\
x = \pm \sqrt{9} \\
x = \pm 3 \\
\\
x = \pm 2, x = \pm 3 \\
\end{IEEEeqnarray*}

\end{document}

Thanks.